Number of Breadcrumbs on Google SERP is one less than it should be

Question

My site has been in existence for more than 2 years now and pages are well indexed in Google. However, I am struggling to get the correct number and type of breadcrumbs despite the long running efforts over the last 2 years:

For instance, on my page, I have setup FOUR levels of breadcrumbs which are as follows:

"@context": "http://schema.org",
  "@type": "BreadcrumbList",
  "itemListElement": [{
    "@type": "ListItem",
    "position": 1,
    "item": {
        "@id": "https://example.com",
        "name": "example.com"
    }
  },{
    "@type": "ListItem",
    "position": 2,
    "item": {
        "@id": "https://example.com/stock/index.php",
        "name": "Major Pharmaceuticals Sector"
    }
  },{
    "@type": "ListItem",
    "position": 3,
    "item": {
        "@id": "https://example.com/stock/list/index.php",
        "name": "Stock List"
    }
  },{
    "@type": "ListItem",
    "position": 4,
    "item": {
        "@id": "https://example.com/stock/list/major-pharmaceuticals.php",
        "name": "List"
}}]

However, there are two problems. On the Google Search Results Page,

1. Only THREE show up as follows instead of the FOUR that I have configured:

https://example.com › Major Pharmaceuticals Sector › Stock List

2. Another problem is that in the first one, it is displaying the name of the website which is set in @id tag. Shouldn't it show the value set in the "name" tag (name example.com) as I've configured in the code?

Above two problems are common to ALL the webpages (and their respective breadcrumbs display). For instance, the page /dividend/thld.php has THREE breadcrumbs but SERP shows only TWO (example.com › Threshold Pharma (THLD) Dividend History)

Am I doing something wrong here or is it the way Google works?